Showing papers on "Cipher published in 1984"

Encrypted broadcast television system

Abstract: A conditional access system for transmitting and receiving scrambled television signals over-air includes means for addressing each of the receiving apparatus with an over-air signal whereby to permit reception and descrambling of the signal. The transmitter is provided with means for assembling a cipher block of information including a first key for use in descrambling the television signal and information relating to a plurality of users, and means for encyphering the cipher block with a second key which is common to the plurality of users. On reception a receiver applies the second, common keys to the received cipher block, recovers the first key for use in descrambling the signal and the information relating to the respective user and descrambles the television signal. Further, it is proposed to transmit a further key in encrypted form and to use the first key to decrypt the further key which is then used to descramble the television signal. This provides a three level key system which is very secure but by using a common second key for a plurality of users, the time to access each user is short.

The Hill cryptographic system with unknown cipher alphabet but known plaintext

Abstract: The cryptographic equations relating plaintext, ciphertext, and key-matrix elements in the Hill system are nonlinear equations if the cipher alphabet is unknown. In the case where plaintext is known it is possible to reduce these equations to linear equations by the introduction of a larger set of unknowns. These latter equations are analyzed by a method of successive eliminations of unknowns from a series of related row-reduced echelon forms.

Remote control locking system

Abstract: A remote control locking system wherein the key comprises a keypad (10) for entering numeric information, a memory storing data relating to a cipher algorithm and means for generating and transmitting, as by infrared radio, a coded pattern of data developed from entered information and the cipher, and the lock has a receiver (18) which identifies the cipher and decodes the coded pattern of data transmitted to it in order to operate the lock.

Ciphering communication system

Abstract: PURPOSE:To improve the intensity of enciphering by providing a function controlling a control signal to a terminal device and an MODEM and a function enciphering all information inputted from a terminal device in a data communication cipher device enciphering the communication between terminal devices. CONSTITUTION:A cipher device at transmission side 2 detects an RS signal from a central processing unit 1 by an RS/CD control section 9 and transmits an open key of the transmission side cipher device 2 from an enciphering and decoding circuit 11 to a receiving side cipher device 6. The reception-side cipher device 6 detects a CD signal ON by the RS/CD control section 9 to transmit the open key of the receiving side cipher device 6 to the transmission-side cipher device 2 and to set a key for enciphering/decoding between the transmission side cipher device 2 and the reception side cipher device 6 to an own enciphering/decoding circuit 11, and the transmission-side cipher device 2 returns the CS signal ON from an interface control section 8 to the central processing unit 1 at the receiving of the open key from the reception-side cipher device 6. Then, the information transmitted from the central processing unit 1 is enciphered and transmitted to a data terminal device 7.

Privacy communication system

Abstract: PURPOSE:To attain the security of information without complicating an enciphering algorithm by connecting a key managing center and each information processor by each separate communication circuit, transmitting an optional key to each information processor through each separate communication circuit from the key managing center, and securing a protocol for enciphering the information between the information processors for transmitting a data. CONSTITUTION:A key table is stored in a key table store part 51 of a key managing center 50, and an optional key in said table is determined by a key determining part, and transmitted to an information processor 10 and a terminal equipment 30, respectively, through communication circuits 41, 42 by a key transmitting part 53. The key transmitting part 53 transmits the key at every one unit or plural units of a communication sentence to the information processor 10 and the terminal device 30. In the information processor 10, the key transmitted from the key managing center 50 is held in a cipher decoding part 11. In the same way, in the terminal equipment 30, the transmitted key concerned is held in the cipher decoding part 31. In this way, a protocol of enciphering is secured between the information processor 10 and the terminal equipment 30.

An Upper Bound on the Key Equivocation for Pure Ciphers

Abstract: An upper bound on key equivocation for a pure cipher applied on a memoryless message source is derived.

Method and device for protecting computer software

Abstract: PURPOSE:To protect software perfectly and surely by enciphering a password, calculating cipher code using random number, obtaining exclusive logical sum of this cipher code and the content of record, and registering in a file CONSTITUTION:When load instruction is generated from the body 10 of a computer to a floppy disk 11, data decoded by a decoding memory 21 are loaded on the RAM of the computer 10 through a contact (a) of a selector 25 In the case of write instruction, data enciphered by an enciphering memory 22 are sent and written to the floppy disk 11 through a contact (a) of a selector 26 The enciphered code is set by a CPU23 for writing cipher code When selectors 25, 26 are switched to a contact (b) by a data bus switching mechanism 24, the data are sent and received between the computer 10 and floppy disk 11 without enciphering and decoding

Privacy telephone system

Abstract: PURPOSE:To attain complete privacy telephone even on a line by using a signal in accordance with plural cipher algolisms and confirming the algorithm information (pattern information) at each call connection between a terminal device and a subscriber circuit at exchange side. CONSTITUTION:A call start signal is incoming to a subscriber circuit 3 by calling of a telephone set terminal 1, the telephone algorithm information is transmitted and received between the terminal 1 and th circuit 3, and the algorithm is decided. This algorithm information is released by a restoring signal at end of call. An A/D conversion control section 22 of a telephone set side decides cipher pattern information by transmitting and receiving it with the exchange side. An analog signal of a telephone set and a digital signal of station side are converted according to the algorithm. A D/D conversion control section 32 of the subscriber circuit 3 is provided with a function of conversion between digital signals of line side and network NW side and confirming and deciding the transmission and receiving of the cipher pattern signal. The signal is converted and transmitted/received between the NW and the line side according to the cipher pattern information.

Setting system of initialized vector in cipher device

Abstract: PURPOSE:To establish quickly the cipher communication without deteriorating the secrecy of cipher and to exclude a transmitting means of a start signal to simplify the constitution of a cipher device, by providing a transmittable signal delay control part to the transmitting part and a transmission data switch control part and a switch circuit to the receiving side, respectively. CONSTITUTION:A cipher device 2 is set between a terminal device 1 and a modulator/demodulator 3 at the transmitting side and then connected via a communication circuit 4 to the receiving side where a cipher device 6 is set between a terminal devie 7 and a modulator/demodulator 5. The demodulator 3 contains a cipher arithmetic device 23 which supplies the transmission data SD and a transmittable signal delay control part 28 which supplies the transmission request signal RS and delivers the transmittable signal CS. While the device 6 contains a cipher arithmetic device 63 which supplies the reception data RD and a reception data switch control part 68 which works on a carrier wave detecting signal CD and controls a switch circuit 69 connected to the device 63. Thus the cipher communication is quickly secured without deteriorating the secrecy of cipher.

Circuit cipher device

Abstract: PURPOSE:To reduce the delay of transmission data and to increases the ciphering intensity by transmitting the initialization vector by a circuit cipher device within a response time when a transmission enable signal arrives to a transmission request signal when viewed from a computer or a terminal. CONSTITUTION:A circuit terminal device receives a transmission request signal RS from a computer or a data terminal, and a receiver 21 of a cipher device receives a transmission enable signal CS1 from the circuit terminal device. Then the signal CS1 is supplied to an interruption generating circuit 17 and a bus driver 18. The circuit 17 transmits an interruption signal IRQ to a CPU15, and the CPU15 transmits a signal corresponding to an address to the driver 18 via an address driver circuit 16 and supplies the output of the driver 18 corresponding to said signal to a data bus. Furthermore the CPU15 transmits an ON signal to a bus receiver 19 and also an initializing vector 23 to an opposite circuit cipher device. After transmission of the vector 23, an FF20 is turned on via the circuit 16. Then a transmission enable signal CS2 is transmitted from a driver 22. This reduces the delay of transmission data.

Personal confirmation system

Abstract: PURPOSE:To increase safety when cipher is carried out with a password as a key by providing a different key to a person individually. CONSTITUTION:A card is put into a reader 13 to read a cipher recorded on the card. The cipher are fed to a register 14. Then an operator feeds a password through a keyboard 1. The keyboard input performs the cipher with the password used as a key. Thus a cipher sentence is produced and fed to a register 15. A comparator 16 compares the contents of the register 14 with those of the register 15. When the coincidence is obtained from this comparison, the confirmation of the corresponding person is possible and displayed at a display part 17.

Data cipher device

Abstract: PURPOSE:To ensure the safe transmission/reception of cipher data, by inhibiting the interruption of a data communication system by setting and comparing the address of own station by a cipher device CONSTITUTION:A data cipher device is set between a data terminal device and a modulating/demodulating device to form a communication system The cipher device is provided with a processing control part 1 which controls the overall system, a panel part 2 which sets the address of own station, a panel control part 3, circuit control parts 4 and 5, a memory 7, a cipher processing part 6, etc Furthermore, the part 1 includes the 1st-3rd registers 11-13, a register control part 10, a comparator 14 and a register switch control part 15 For the memory 7 the comparator 14 compares the address of own station set through the part 2 with reception addresses of registers 11-13 Then an address sent to the own station is decoded at the processing part 6 and then sent to a terminal of own station While the cipher data is sent at it is to the terminal of own station when no data is addressed to the own station This device ensures the safe transmission/reception of the cipher data

Cipher communication method

Abstract: PURPOSE:To automatically perform communication with a communication procedure control signal which is not ciphered irrespectively of whether or not a receiver is equipped with a cipher decoder, by including information indicating that whether or not the receiver is equipped with a cipher decoding device in the communication procedure control signal, and performing ciphered communication only when the receiver is provided with the decoder. CONSTITUTION:In response to a call from a transmitter 1, the circuit between the transmitter and a receiver 2 is connected and the transmitting function and receiving function of the transmitter 1, and receiver 2 are mutually confirmed. Then a control signal outputted from a communication controlling circuit 5 is inputted into the signal input terminal 22 of the receiver 2 from a signal output terminal 23 through the circuit without being ciphered and further inputted into a communication controlling circuit 13 without passing through a decoding circuit 16. A receiving function discriminating signal including information indicating that whether the receiver 2 is equipped with a cipher decoding function or not, is transmitted from the communication controlling circuit 13 to the transmitter 1. Upon receiving the discriminating signal, the communication controlling circuit 5 of the transmitter 1 sends a mode setting instruction signal including information indicating that ciphered transmission is performed as the response. When the information indicating that ciphered transmission is performed is included in the mode setting instruction signal, the communication controlling circuit 13 of the receiver 2 controls a multiplexer 15 so as to select the output of the decoding circuit 16.

Cipher machine inventor - boris hagelin dies

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Decoding circuit of cipher

Abstract: PURPOSE:To transmit program cipher keys to a receiving terminal collectively by extracting key distributing data, and code-converting the remainder obtained by dividing the extracted data by the previously fixed number to use as a cipher key. CONSTITUTION:Integers q1-qN which are primes each other are fixed in terminals 1-N. A transmitting station adds a previously fixed pattern P to a binary pattern indicating K+cq1-qN (c is the transferred number) to transmit the added pattern. A pattern detector 102 detects the pattern P from binary data inputted to a terminal 104 of a receiver and transfers the digital data with the previously fixed length which is transmitted after the pattern P to a remainder unit 103. The remainder unit 103 divides the digital data by an integer qi inputted from an input terminal 105 and sends the remainder K as a cipher key to a decoder 101, which decodes the data by using the cipher key as a key until the succeeding pattern P arrives. Thus, the keys can be collectively transmitted to the terminal, so that the time of decoding can be shortened.

Open key delivery system

Abstract: PURPOSE:To secure the certification between counter cipher devices of an open key delivery system by ciphering and delivering open keys to each other to obtain the open keys through decoding of each cipher device, and producing a basic key from those open keys. CONSTITUTION:An open key is ciphered by a cipher key and sent from the remote side. This ciphered open key is supplied to a data ciphering standard arithmetic part 22 via an input register 20. In such a case, a cipher key K is delivered from a key generator 13 via a key register 21. Thus the part 22 performs decoding with the key K to obtain an open key. This open key is selected by a selector 24 via an output register 23 and supplied to the generator 13. A cipher sentence coded by a station of the remote side is supplied to the part 22 via the register 20, and decoded to an original normal sentence by the key K.

Key locking sysem of keyboard

Abstract: PURPOSE:To reduce the mounting cubic volume of a keyboard and its cost, by detecting a continuous depression of an existing specified key of the keyboard and depression of other specified key, and executing key locking or its release. CONSTITUTION:When a specified A key 2 is depressed continuously >=3 times at such time intervals as a one shot circuit 4 is not reset, an output of a flag 5 goes to ''1'', a signal KEYSTB is outputted whenever the key 2 is depressed, outputs of flags 9-11 all attain level, and a gate 12 outputs one level. When the key 2 is depressed odd times, an output of a flag 13 is inverted to ''1'' from ''0'', an output of an invertor 21 goes to ''1'', and gates 23-25 are enabled. In this state, when a B key 31 designated as a cipher key is depressed, exclusive cipher codes are outputted from SWs 27-29 by an encoder 26, are sent to flags 15-17 through the gates 23-25, are latched, and a key locking signal is outputted from a gate 22 through gates 18-20. In case when the key 2 is depressed even times, the output of the flag 13 is inverted to ''0'' from ''1'', and the key locking is released.

Interface control system

Abstract: PURPOSE:To update cipher data without altering the communication function of an objective data communication system by setting a cipher data setting period shorter than a response time permitted for a data transmitter and receiver CONSTITUTION:Data communication enciphering devices 6 and 7 are interposed between a central processor 1 and a modulator-demodulator 3, and a modulator- demodulator 4 and a data terminal device 2 The enciphering device 6 returns a transmission permitting signal (CS) to the processor 1 within the permissible response time in response to a transmission request signal (RS) generated by the processor 1 during the communication period of the ciphering devices 6 and 7 for setting cipher data K The processor 1 receives the signal CS and sends out transmit data SD, which is discarded during the communication of cipher data K and enciphered by the enciphering device 6 by the cipher data K after the communication of the cipher data K and outputted In this case, a cipher data communication time is set within the permissible response time of the transmit data SD

Key distribution system of cipher device

Abstract: PURPOSE:To produce a common key by using the preparation end signal of a data terminal device of the called side as a trigger to perform an operation between the cipher devices of transmission and reception sides with an open key distribution system. CONSTITUTION:An MODEM5 of the called side receives a dial signal, and a call signal is turned on. Then a terminal preparation end signal ER is turned on for a terminal device DTE7. The ON of a DR signal transmitted from the MODEM5 is received after the ON of the signal ER is received from the device 7. Then a cipher device 6 of the called side starts an open key distribution system PKDS. The produced key information X is sent to the calling side from the called side. Then a positive answer signal and the produced key information Y are sent to the called side, and the called side performs transmission in the same way. Thus the produced keys are set at both sides.